ERROR: Package 'hermes-agent' requires a different Python: 3.14.6 not in '<3.14,>=3.11'

Why it happens

pip compares your interpreter with the requires-python field in the Hermes package metadata. Up to v0.21.5 the ceiling was below 3.14 because some Rust-backed dependencies had no 3.14 wheels yet.

1. You installed with pip install hermes-agent. PyPI still serves 0.19.0 from July 2026, which declares <3.14,>=3.11, so it fails on any 3.14 interpreter.
2. Your platform now ships 3.14 as the default python3: Termux (python package 3.14.6), Homebrew (brew install python now installs 3.14) and Fedora 43.
3. You are installing or updating a checkout or package pinned to v0.21.5 or older. The v0.21.6 notes say the Desktop app and Termux packages stay on their current build until the next bundled release.
4. A UV_PYTHON=3.14 variable inherited from your shell made uv pick 3.14 for an older Hermes build.

The fix

1. 1 Check what you have: python3 --version, and hermes --version if Hermes is already installed.
2. 2 Preferred: get v0.21.6 or later. Re-run the installer, curl -fsSL https://hermes-agent.nousresearch.com/install.sh | bash, or on Windows iex (irm https://hermes-agent.nousresearch.com/install.ps1). Existing git installs can run hermes update.
3. 3 If you need an older build, install 3.13 alongside 3.14: uv python install 3.13, or brew install python@3.13, or pyenv install 3.13, or on Termux pkg install tur-repo && pkg install python3.13.
4. 4 Create the environment on 3.13 explicitly: uv venv --python 3.13, then install into that venv. On Windows use the launcher: py -3.13 -m venv .venv.
5. 5 Unset any UV_PYTHON=3.14 in your shell before installing.
6. 6 Run hermes doctor. Its Python line shows the interpreter Hermes is actually running on.

Did a recent Hermes release lift the 3.14 cap?

Yes, in v0.21.6. At v0.21.5 (tag v2026.9.24) pyproject.toml still read requires-python = ">=3.11,<3.14", with a comment that 3.14 was blocked until pydantic-core and other Rust dependencies shipped cp314 wheels.

At v0.21.6 (8 October 2026) and on main it reads ">=3.11,<3.15", the repo's .python-version is 3.14, and the installer bootstraps Python 3.14 by default. The comment says older versions are still allowed only so that old installs can get through their update step.

So on a current install the advice flips: 3.14 is the target, not the problem. The error now only comes from old builds, the PyPI package, or the Desktop and Termux builds that have not moved yet.

Still failing?

• Run which -a python3 (or py --list on Windows) to see every interpreter on PATH; the installer may be finding a different one than you expect.
• If hermes update itself fails with this error, re-run the installer one-liner instead, since an old updater can still be resolving against the old range.
• On Termux, if no 3.13 package is available, wait for the next Termux build of Hermes or run Hermes inside proot-distro with a full Linux userland.

Related errors

• "command not found: hermes" after install
• Hermes "No module named 'hermes_cli'" after update